1. Field of the Invention
This invention relates to hose constructions and in particular to hose constructions utilizing thermoplastic core tubes.
2. Description of the Prior Art
In the construction of hose, a tubular core is overlaid with a reinforcement layer which imparts strength and burst resistance to the hose. It is desirable to provide a reinforcement layer which maintains substantial flexibilty in the hose and which is kink-resistant while yet providing the desirable reinforcement function. A large number of different types of hose constructions have been developed over the years providing different desirable features and utilizing a wide range of materials. Further, a number of different techniques have been utilized for bonding the reinforcement layer to the outer surface of the core tube.
In certain conventional hose constructions, an outer sheath is further overlaid about the reinforcement layer and, here again, a large number of different materials and techniques for bonding the sheath to the reinforcement layer have been developed.
Examples of a number of such improved hose structures include those disclosed in the Harold E. Jackson et al. U.S. Pat. No. 3,172,427 wherein a reinforcement layer is disposed in tensioned relationship about a nylon core tube.
Another improved hose structure is disclosed in the Marvin E. Holmgren U.S. Pat. No. 3,186,438 wherein a nylon core tube is provided with a polyester reinforcement layer and a ribbed outer sheath.
In U.S. Pat. No. 3,233,024 of Harold E. Jackson et al., a hose is formed by applying a polyester braid around an extruded nylon core tube. Upon extrusion of a sheath thereabout, the composite hose is cooled by an improved cooling device.
In Edward J. Ross U.S. Pat. No. 3,266,527, a sheath layer is heat shrunk onto the core tube prior to the application of a reinforcement layer thereabout. The different layers of the hose may be bonded to one another by suitable adhesive materials.
In Marvin E. Holmgren U.S. Pat. No. 3,332,447, an adhesive is used to secure different portions of the hose structure together by both cross-linking and heat fusible modes. The adhesive coated hose is heated to dry off solvent from the adhesive and cause cross-linking agents of the adhesive to cross link with the molecular structure of the reinforcement layer. The core tube may be formed of a heat fusible or cross-linkable material.
A hose construction is disclosed in the Thomas F. Rider U.S. Pat. No. 3,633,629 wherein the reinforcement layer includes two different types of fibers, one of which is thermally fusion bonded to the core and the other of which is free for movement relative to the core. The core surface is raised to fusion temperature by a heating coil immediately before application of the reinforcement layer. A coolant fluid may be circulated through the core tube to maintain the internal stability thereof during the application of the reinforcement layer.
In U.S. Pat. No. 3,721,271 of Anil H. Chudgar, a hose construction is disclosed wherein nylon reinforcement layer fibers are autogenously bonded to the nylon tube core by a nonsolvent agent.
In U.S. Pat. No. 3,373,089 of Anil H. Chudgar, a nonsolvent nylon softening agent is utilized to soften the outer surface of the nylon core tube and permit mechanical interlocking of the reinforcement layer fibers therewith upon resetting of the core tube surface.
The above discussed prior art patents are owned by the assignee hereof. Prior art hose constructions of others include those of Richard A. Matthews U.S. Pat. No. 3,116,760 wherein a polyurethane adhesive is used to bond the reinforcement layer to a polyurethane core tube. In a Richard A. Matthews U.S. Pat. No. 3,722,550, the core tube includes a peripheral adhesively activated zone. The activation material of the adhesive penetrates into the core tube and after the reinforcement layer is applied, a predetermined period of time is required to enable substantially complete evaporation of the activation material to provide the desired bond between the core tube and reinforcement material, this period being disclosed as about 8 to 36 hours.
In Alfred R. Phillips et al. U. S. Pat. No. 3,726,321, an elastomeric adhesive is applied on the core tube which, after the reinforcement layer is applied, is allowed to set and maintain an elastomeric adhesive bond therebetween.
In the prior art manufactures using solvent or other fusion means, control of penetration into the yarn has been difficult.